ZIPPERING AND INTERMESHING - NOVEL PHASE-DIAGRAMS FOR INTERFACES AND FILMS

New surface and layering phase diagrams are proposed based on generali zed sine-Gordon models with and without a substrate potential. In part icular, we find that the preroughening transition can be driven first order, explaining ''zipper'' features in heat capacity data for argon and krypton on graphite substrates. For different parameters, we predi ct the existence-of a novel variant of disordered flat phase with spon taneously broken particle-hole symmetry and continuously varying surfa ce height with an accompanying intermeshing layering;phase diagram. Th e restricted solid-on-solid model displays zippering for sufficiently large second neighbor coupling.